Apparatus for producing sand cores and the like



March 20, 1951 R, R, SNOW 2,545,799

APPARATUS FOR PRODUCING SAND CORES AND THE LIKE Filed April 26, 1946 3Sheets-Sheet l N @Zen (521011.?

2,545,799 APPARATUS FOR PRODUCING SAND C ORES AND THE LIKE Filed April26, 1946 R. R. SNOW March 20, 1951 s Sheets-Sheet 2 March 20, 1951 R. R.sNow APPARATUS FOR PRODUCING SAND CORES AND THE LIKE Filed April 26,1946 3 Sheets-Sheet 5 3 o ew 2 0120a Patented Mar. 20, 1951 APPARATUSFOR PRODUCING SAND CORES AND THE LIKE Robert R. Snow, St. Catharines,Ontario, Canada,

assignor to General Motors Corporation, Detroit, Mich., a corporation ofDelaware Application April 26, 1946, Serial No. 665,231

7 Claims. (01. 22-10) This invention relates to an apparatus forproducing sand cores and the like.

Among the objects of the invention are the following: to provideimprovements in apparatus for producing cores and the like; to provideimprovements in core making apparatus and the like wherein theoperations are largely automatic; to provide improvements in apparatusfor producing cores and the like whereby there is a saving of labor andwhereby heavy labor commonly associated with core making has beenlargely, if not entirely, eliminated; to provide improvements in coremaking apparatus whereby cores can be more accurately formed on accountof being automatically drawn by the apparatus, thus eliminating humaninaccuracies; and to provide improvements in core making apparatuswhereby the core boxes are quickly interchange.- able. Other objects andadvantages of the invention will become more apparent as the descriptionproceeds.

The accompanying drawings forming a portion of this specificationillustrate a machine in 2.0-- cordance with one embodiment of theinvention.

In the drawings:

Figure 1 is an elevational view of the machine.

Figure 2 is a diagrammatic view showing the relative position of.certain parts of the machine at one point in a cycle of operation.

Figure 3 is a view illustrating the means for intermittently rotatingthe turntable of the machine and for actuating control cam means.

Figure 4 is a diagrammatic showing of one form of hydraulic controlsystem .or circuit and illustrating the manner in which the severaloperations are hydraulically operated and com trolled.

Fig. 5 is a somewhat diagrammatic view showing one form of means forrotating a core box part carried by the turntable of the machine.

Figure 6 is a diagrammatic view illustrating a magnetic means andcontrol system for picking up a core box top from one position andmoving the same to another position.

Figure '7 is a view with parts broken away and parts in sectionillustrating an evener device.

General description so that it can be turned 180 at certain points inthe cycle of operation of the machine. The

turntable and arms are driven by an electric motor and speed reducingmeans mounted in the base of the machine. The turntable is so controlledthat it rotates 90 at a time and indexes accurately into any one of fourpositions. At one station (hereinafter considered as the first stationor station No. I) a core box top is raised automatically from theturntable, moved in a horizontal plane to a position over the lower halfof the core box carried by the arms and finally lowered into position onthe bottom half of the empty core box. At the same time a core box topis being removed from a filled core box at a station 180 from the firststation, then moved in a horizontal plane above the turntable and thenlowered into a position on the turntable. The core box top removed fromthe filled core box then moves with the turntable until it is inposition at station No. I where it is in position to be picked up andplaced on the bottom of the core box.

Th means for raising, lowering and moving the upper parts of the coreboxes comprises electromagnets and hydraulically operated means whichraise and lower the magnets and which move the magnets in a horizontalplane when they are in their raised positions.

The station spaced 180 from the first may be considered as station No. 3as there is a station 90 from station No. I atwhichthe core box isfilledwith core sand by a core blowing machine. The core blowing station maybe considered as station No. 2. After the upper half of the core box isremoved from the lower half at station .No. -3 the operator places acore drier over the sand core and fastens it in place to the lower halfof the core box. The turntable then rotates 90 to station No. 4 wherethe core is drawn. During rotation of the turntable from station No. 3to station No. 4, the lower half of the core box, with the core and thecore drier, is caused to revolve 180 on its horizontal axis, thusturning it upside down. With the turntable Stationary at station No. 4,a hydraulic piston raises a plate or table under the core drier andcore. The plate carries an evener device which is Operated automaticallyby air pressure, The purpose of the evener is to ensure that thepressure on the core .drier is uniform at all points of contact, tocompensate for-any irregularities in the shapes of the various corediners and to produce a core drawing operation at right angles to theparting line. The turntable then automatically moves 90 to station No. land during its movement the lower half of the core box revolves 180 onits 3 horizontal axis, thus turning it right side up. When at thisstation the bottom half has its top half placed thereon as previouslydescribed.

Detailed description The embodiment of the invention shown in thedrawings comprises an apparatus for producing sand cores and the likefor use in foundry operations. Referring to Figure l of the drawings IE]is a housing above which is a turntable l 2 having four pairs of armsI4, each pair being90 from the next adjacent pairs (see also Figure 2)Each pair of arms adjacent its outer ends has the bottom half is of acore box carried thereby and so mounted that the same can be turned 180on a horizontal axis. by ll. Above the turntable is a slidable member i3carrying at each end similar electromagnets 20 and electrical andhydraulic devices foriactuating the same. Slide I8 is moved in ahorizontal plane by means of a hydraulic cylinder 22, piston 24 (seeFigure 4) and rod 26. The cylinder 22 is fixed to a stationary support23, which in turn is carried by the upper portion of a stationary postindicated generally by 25. The magnets 20 are actuated in a verticaldirection by means of similar hydraulic cylinders 28, pistons 30(seeFigure 4) and piston rods 32. The cylinders 28 and associated partsare carried by the slide Hi. In Figure l the slide 58 is shown in itsright hand position and the magnets are shown in lowered positionscontacting the upper halves ll of the core boxes at stations I and 3. Assoon as the electromagnet atstation 3 has removed the core box top fromthe filled core box, the operator places a core drier over the core sandand fastens 'it in place to the lower half of the core box by clamps.

In order to properly handle the upper half of the core box by theelectromagnet, it is necessary to have the body of the box made ofnon-magnetic material (aluminum) to the top of which is fastened a fiatsteel plate to be attracted by the magnet when energized.

At the right hand side of the housing It] (Fig- .ure 1) is shown a'meansfor looking or holding 'on a piston rod 43 and during vertical movementis guided by two vertical rods 44. The piston rod 43 is connected at itsopposite end to a piston 46 in a cylinder 43 and is caused to move upand down by the pressure of oil or other suitable fluid in the cylinder.Mounted on the plate 42 is an air cylinder 58 which is supplied by airpressure through a flexible hose 52. The air is regulated by a controlvalve 53 operated by a solenoid 54.

The solenoid is energized by limit switch 65 actuated by an adjustablescrew 66 movable with the table 42. In the air cylinder 50 are twopistons 55 free to move horizontally and by means of piston rods 55apply pressure against the hubs 5B of four leveling fingers representedgenerally by El! (Figures 1, 4 and '7). Each leveling finger alsoincludes an arm portion 5! connecting the hub portion 5 8 with a portion60' of a leveling The core box tops are indicated 4 finger adapted tocontact the core drier. Between the hubs of the leveling fingers aresimilar fiber washers 62. Each piston rod 56 has a portion 59 at its endaway from its piston 55 of smaller diameter than the portion adjacentits piston, thus forming a shoulder at the junction between the twoportions. Between each shoulder and the adjacent fiber washer 62 is awasher 61 of stepped shape in cross section. The portion 59 of eachpiston rod passes through a washer 6!, two fiber washers 62, and the hubportions 58 of two leveling fingers. Thus the leveling fingers arepivoted about the portions 59 of the piston rods. Stops 63 are fixed tothe plate 52. The leveling fingers are biased in upward position bymeans of springs 64 which have one end of each in contact with the plate42 and the opposite end of each contacting the underneath portion of thefree end of a leveling finger away from its hub which is pivoted on apiston rod portion 59. The operation of the core drawing means is asfollows: Oil under pressure is admitted to the cylinder #8 which raisesthe plate on table 42 and parts carried thereby under the core to bedrawn. The leveling fingers make contact with the bottom of the coredrier [5 (Figure 1) and adjust themselves by pivotal movement of theirhubs on the piston rod portions 59. This compresses each spring 66slightly. Air is now admitted to the air cylinde 50, the pistons 55therein are forced outwardly a small distance. This outward movement ofthe pistons causes corresponding movement of the piston rods 56 so thatthe shoulders formed thereon force the washers 6 I, 62 and hubs 58outwardly and tightly clamp or squeeze the same between the shoulder andstops 63, thereby holding the fingers in'position. In other words thesqueezing action applies pressure to the sides of the hubs 58 andwashers whereby frictional forces therebetween hold the fingers againstpivotal movement on the smaller diameter portions 59 of the piston rods.Latches holding together the core dried and inverted bottom part of thecore box are tripped open and oil pressure .is removed from cylinder 48,allowing the plate or table 42 to move down carrying the core drier andcore with it to a position from which they may be removed by theoperator. The core drier and core may now be placed in an oven forbaking the core.

During movement of the turntable from station 3 to station 4 the bottomhalf of the core box and the core drier fixed thereto are rotated 180 toinvert the same. During movement of the turntable from station 4 tostation I the inverted bottom half of the core box is rotated 180 toagain bring the same into its right side up position so that the tophalf of the core box can be placed thereon at station l.

The means for rotating the bottom portion of the core box, etc., as justdescribed, is illustrated in Figures 1 and 5. Carried by the turntableis an electric motor 70 connected to a gear pump 12. The inlet side ofthe pump is connected by pipe 74 to an oil supply tank T6. The outletside 18 of the'gear pump leadst'o a volume control and then to afour-way valve 82 having an actuating element 19. The actuating elementof the 'four-way valve is operated by a stationary cam 8 mounted abovethe turntable, said cam being fixed to post 25. Oil, controlled by thevalve 82, enters a cylinder 88 carried by the turntable causing a piston88 to move a chain turning sprocket 9| is fixed to a shaft 89 which, inturn, is fixed to the bottom of a core box. The movement of the piston86 is just suific'ient to rotate 180 the bottom of the core box with thecore drier clamped thereto. The foregoing action takes place while theturntable is moving from station 3 to station 4. When the cam 84 disengages the actuating element 19 of the valve 82 (by movement with theturntable of the valve 82 and its adjusting element 19 past the cam) theoil pressure is reversed in cylinder 86 thereby moving piston 88 in thereverse direction and causing the return of the bottom of the core boxto its original right side up position. This action takes place whilethe turntable is rotating from station No. 4 to station I.

After the turntable has moved to station No. I and a core box topapplied thereto as previously described, the now closed core box ismoved to station No. 2 where the core sand mixture is blown into thecore box by a core blowing machine of any conventional designautomatically controlled by operation of the core making machine.

In Figure 3 is illustrated a means whereby the turntable may beactuated, the mechanism shown being located in the housing I 8. Anelectric motor 96 rotating at constant speed drives a rotating disc 98at a constant speed. A suitable variable speed means 89 and speedreducing device I00 reduce the speed of the rotating disc greatly ascompared with that of the electric motor. For each revolution of thedisc 68 the turntable I2 is indexed 90 by means of a ratchet clutch I 02which drives the turntable shaft I04. In Figure 3 is shown a camshaftI06 which rotates continuously at constant speed. The camshaft is drivenby the electric motor and speed reducing means by means of a chain orbelt I01. To the camshaft are fixed a plurality of control cams foroperating various hydraulic controls, one of these cams I08 being shownin Figure 3.

Figure 4 shows what may be considered as the main hydraulic system andillustrates the man-' to the tank I24 by means of a return header I30.

In Figure 4 are shown cams I08, I06, H0, III, H2 and I I3 which controlvarious hydraulic circuits. It will be understood that the cams I08 toH3 inclusive are rotated by the camshaft I06 which rotates continuouslywhen the machine is being operated.

Cam I08 operates a pilot valve I 32 which causes a four-way valve I34 toallow oil under pressure to enter one end of cylinder 22 (see alsoFigure l), to thereby move the piston 24 in one direction. This causesthe slide I8 and two magnets 20 carried thereby to traverse to one endof the stroke. Further rotation of the cam I08 causes reverse operationsof the pilot valve I32, fourway valve I34 and piston 24. This causes theslide and magnets to traverse to the opposite end of the stroke. Avolume control I36 is provided in the line leading from the highpressure header I26 to the four-way valve I34 to regulate the speed atwhich piston 24 travels. Oil line I31 leads from the four-way valve I34to the return header I30.

Cam I09 actuates a pilot valve I40 which controls a four-way valve I42which in turn allows oil under pressure to enter one end of hydrauliccylinders 28 (see also Figure 1). These cylinders operate in parallel.Oil pressure in the cylinders 28 cause the pistons 30 therein to move inone direction to simultaneously raise the two magnets 20. Furtherrotation of the cam I09 reverses the operation of the four-way valve I42to move the pistons 30 in the opposite direction in cylinders 28 tolower the magnets simultaneously. A vol ume control I44 is provided inthe line leading from the header I26 to the four-way valve I 42 toregulate the speed of travel of pistons 38 in cylinders 28. Oil isreturned to the header I30 from the four-way valve I42 by oil line I45.

Cam H0 actuates a four-way valve I48 which controls flow of oil underpressure from header I26 to the opposite sides of piston I50 inhydraulic cylinder I52. Movement of the piston I50 operates air valveI54 on the core blowing ma chine I56. Oil line I51 leads from the valveI48 to return header I30.

Rotation of cam I I I actuates a four-way valve I58 which causes oilunder pressure to enter cylinder 36 to thereby move the piston 31therein in one direction to move the dog 40 into the V-notch 32 andthereby hold the turntable I2 in indexed position. Oil under pressurealso flows into one end of a cylinder I60 to move a piston I62 thereinto apply a brake I64 to the turntable driving shaft. Further operationof cam I II causes reverse operations of the four-way valve and pistons31 and I62 to release the dog 40 from the v-notch 32 and to release thebrake. By means of line I65 oil is returned to header I30 for return totank I24.

Rotation of cam II2 actuates a four-way valve I68 which causes oil underpressure from header I26 to enter one end of a cylinder I10 and movepiston I12 therein in one direction to move the hopper I14 of the coreblower to operating position at station No. 2. Further rotationreversesthe operation of the four-way valve and piston I12 to therebymove the core blower hopper to inoperative position away from theturntable. Oil line I15 leads from the valve 168 to the return headerI30.

Rotation of cam II3 operates a four-way valve I16 which causes oil underpressure to enter one end of cylinder 48 to raise the piston 46 thereinand plate 42 of the core drawing mechanism at station 4. Furtherrotation of cam I I 3 causes reverse operation of the four-way valve I16and piston 46 to lower the core drawing mechanism. A volume control I 18is provided in the line leading from the header to regulate the speed ofthe piston 46. Oil is returned by pipe I18 from the four-way valve I18to the return header I30.

The electric circuit for one of the magnets is illustrateddiagrammatically in Figure 6. The circuit for the other magnet is thesame as that illustrated in Figure 6. For lifting the top halves of thecore boxes the magnets are energized by current flowing in one directionthrough the magnet coils. To release the top halves of the core boxesreverse current is temporarily passed through the magnet coils todestroy residual magnetism. In the position shown in Figure 6 the magnet26 is in elevated position above the core box. Upon downward movement ofthe mag net, by means of the hydraulic cylinder 28, piston 30 and rod32, the limit switches 228 and 229 are actuated causing 228 to close and228 to open. Switches 228 and 229 are mounted on each end of the magnetand are caused to operate by mechanical contact with the top of the corebox. At this time switches 230 and. 23I are in their normally closedpositions. A circuit is then established from Ll, connections 239, 246,242, switch 23!, connection 244, switch 228, connection 245, switch 236,connection 248, and then by parallel circuits through the coils ofcontactor CRi and time relay TR! to L2. Ihe circuit from 248 through thecoil of CR! is by connector 258, coil 252 of CR1, and connector 254 toL2. The circuit from 248 through the coil of TB! is by means ofconnector 256, coil 258 of TRI, and connector 260 to L2.

Energization of coil 255 of TR! actuates an arm 253 carrying blade 26!which closes contact 221. Energization of the coil 252 of CR! raises anarm 262 carrying blades 264, 266, and 268, which close contacts 22!, 223and 232 respectively. This energizes the magnet by means of the circuitfrom Li, contact 22i closed by blade 254, connector 216, magnet coil222, connector 212, contacts 223 closed by blade 266, and then to L2.lhe hydraulic cylinders then lift the magnets and core box tops. Thereis mechanical lag which allows the limit switches 228 and 229 to returnto normal positions (switch 228 open and 229 closed) before the core boxtop is moved. A circuit is then established from L! through connector239, conductor 2451, switch 229, connectors 216 and 218 to contact 232closed by blade 268, connector 236, coil 252 and connector 254 to L2. bymeans of connector 242, switch 23! and connector 244 to connector 218.Circuit portions 256 and 256, coil 258 of TRl, and connector 260 to L2are in parallel circuit relation with the corresponding circuit throughthe coil 252 of CRI. The foregoing circuit holds while the magnet andtop half fo the core boxes are lifted full height by hydraulic cylinder28 and traverse-d to the opposite end of the horizontal traverse ofslide it by hydraulic cylinder 22. At this time limit switches 235 and23l are opened by member 233 carried by the slide. Circuit from Ll to L2is then from 239, 256, 229, 216, 2718, contact 232 closed by 268, 286,and then through the coils of CR! and TR! in parallel to L2.

The magnet 26 is then lowered to set the top half of the core box on theturntable or onto an empty lower half of a core box, as the case may be.When the mechanical slack is taken up the limit switch 228 is closed and225 is opened. Opening of.229 (since 23! has been opened previously asdescribed) cuts off current from coil 252 of CRI and coil 258 of TRI,thus deenergizing the same. Although coil 258 of TRI is now deenergizedthe blade 25! still closes contact 221 for a period of about twoseconds. Deenergizing coil 252 of CR! causes blades 264 and 266 to dropdown closing back contacts 225 and 224 respectively. A demagnetizingcircuit is then set up through the coil 222 of the magnet 26. Thiscircuit is from Ll through 239, back contact 224, connection 212,magnetizing coil 222, connector 216, back contact 225 (closed by 264),connector 290, current limiting resistor 226, contact 22'! still closedby 26i, and connector 266 to L2. At the end of about two seconds theblade 26A of time delay relay opens contact 22? to open the demag- Acircuit is also established from 2413 apparatus constructed inaccordance with a spe-:

cific embodiment of my invention it will be apparent that I haveprovided a core making machine adapted for automatic operation and atadjustable speed so that the operation can be timed to suit the coresbeing produced. Also provided is a power driven, accurately indexed, andautomatically operated turntable. The machine further includes automaticmeans for turning over the core box containing a core, automatic meansfor blowing the core and automatic means for drawing the core.

It will be understood that various changes and modifications in thespecific embodiment of the invention described in detail herein, may bemade without departing from the spirit and principles of my inventionand I do not intend to limit the patent granted for my invention exceptas necessitated by the prior art.

I claim:

1. In apparatus of the class described, a turntable, a plurality of coreboxes carried by the turntable, means for rotating the turntable to aplurality of stations, one of said stations being a core box topremoving station and a diametrically opposite station being a core boxtop replacing station, a slidable member above the turntable movablehorizontally back and forth in the vertical plane through the axis ofthe turntable and said core box top removing and replacing stations, anelectromagnet at each end of the slidable member, hydraulically operatedmeans for moving the slide and electromagnets in a horizontal planeabove the turntable, hydraulically operated means carried by the slideto move the two electromagnets in unison in a vertical direction whilethe slide is at each end of its path of travel, means for energizing theelectromagnets to pick up core box tops when the slide is at one end ofits travel and after lowering of said electromagnets into contact withsaid core box tops, means for maintaining the energization of saidelectromagnets while the electromagnets are raised, while they are movedby said slide to the opposite end of its path of travel and while theylower the core box tops carried thereby, and means for deenergizing theelectromagnets to release the core box tops after the electromagnetshave been lowered at said opposite end of the path of travel of saidslide.

2. In apparatus of the class described, a turntable, a plurality of coreboxes carried by the turntable, means for intermittently rotating theturntable to a plurality of stations, one of said stations being a corebox top removing station and a diametrically opposite station being acore box top replacing station, a slidable member above the turntablemovable horizontally back and forth in the vertical plane through theaxis of the turntable and said core box top removing and replacingstations, an electromagnet at each end of the slidable member,hydraulically operated means for moving the slide and electromagnets ina horizontal plane above the turntable, hydraulically operated meanscarried by the slide to move vertically the two electromagnets inunison, automatic means for energizing the electromagnets to pick upcore box tops when the slide is at one end of its travel and afterlowering of said electromagnets, for maintaining the energization ofsaid electromagnets while the electromagnets are raised, while theelectromagnets and core box tops are moved by the slide to the oppositeend of its path of travel and while the electromagnets are lowered andfor deenergizing the magnets to release the core box tops after theelectromagnets have been lowered ing the turntable in a stationaryposition during movement of the slide and electromagnets.

3. In an automatic core making machine having a core blowing station, acore drawing station, a core box top removing station and a core box topreplacing station; a turntable; a core box carried by the turntable;mechanism for rotating the turntable to said plurality of stations;mechanism for placing a core box top on the bottom of a core box at oneof said stations consisting of a horizontally movable slide above theturntable and a vertically movable device carried by the slide adaptedto raise a core box top from the turntable when the horizontally movableslide is in one position of movement and to place the same on the bottomof a core box when the slide is at another position of movement;mechsaid turntable and then placing the same on.

the turntable at a point radially inward of the bottom of the core boxfrom which the top was removed, and control means for sequentiallyactuating said mechanisms at said stations.

i. In apparatus of the class described, a turntable, four core boxescarried by the turntable at 90 intervals, automatically operatedmechanism for rotating the turntable sequentially to four stations at 90intervals, the first station being a station at which a core box top isplaced on a core box bottom, the second a core blowing station, thethird a core box top removing station and the fourth a core drawingstation, a horizontally movable slide above the turntable in thevertical plane through the axis of the turntable and stations one andthree, and vertically movable mechanism at each end of the slide to pickup a core box top from a filled core box on the turntable at stationnumber three at the same time that a previously removed core box top isbeing picked up from the turntable at station number one and while theslide is at one end of its path of travel, said vertically movablemechanism placing the core box top picked up from the filled core box atstation number three onto the turntable and placing the core box toppicked up from the turntable at station number one onto a core boxbottom when the slide is at the other end of its path of travel.

' 5. In an apparatus of the class described, a turntable, four coreboxes carried by the turntable at 90 intervals, automatically operatedmechanism for intermittently rotating the turntable 90 at a time to fourstations with a core box at each station, the first station being astation at which a core box top is placed on a core box bottom, thesecond a core blowing station, the third a core box top removing stationand the fourth a core drawing station, a member above the turntableslidable horizontally back and forth in the vertical plane through theaxis of the turntable and stations one and three, a first cylinder andfluid pressure actuated piston for moving said slidable member back andforth, a cylinder carried at each end of said slidable member, a fluidpressure actuated piston in each cylinder at each end of the slide andmovable in a vertical direction, an electromagnet movable by each vcriically movable piston, fluid pressure connections to said firstcylinder for actuating the piston therein to move the slidable memberback and forth, fluid pressure connections to each of the cylinderscarried at the ends of the slidable member to move the pistons thereinand the two electromagnets in unison in a vertical direction when theslide is at each end of its path of travel to sequentially raise andlower the two electromagnets, and electrical circuits to energize thetwo electromagnets when they are lowered onto the two core box tops onthe turntable at stations one and three, to maintain the energization ofthe two electromagnets while the two vertically moving pistons aremoving upwardly, while the slide is moving to the other end of its pathof travel and while the vertically moving pistons are being lowered, andthen to deenergize the two electromagnets to thereby release the twocore box tops, one of them being released on a core box bottom at thefirst station and the other being released onto the turntable at thethird station at a point radially inward of a filled core box.

6. In an apparatus of the class described, a turntable, four core boxescarried by the turntable at intervals, a continuously rotating member,mechanism actuated by the continuously rotating member forintermittently rotating the turntable 90 at a time to four stations witha core box at each station, the first station being a station at which acore box top is placed on a core box bottom, the second a core blowingstation, the third a core box top removing station and the fourth a coredrawing station, a member above the turntable slidable horizontally backand forth in the vertical plane through the axis of the turntable andstations one and three, a first cylinder and fluid pressure actuatedpiston for moving said slidable member baok-and-forth, a cylindercarried at each end of said slidable member, a fluid pressure actuatedpiston in each of the cylinders at the ends of the slidable member andmovable in a vertical direction, an electromagnet movable vertically byeach vertically movable piston, means for admitting fluid pressure tosaid first cylinder for actuating the piston therein to move theslidable member back and forth, means for admitting fluid pressure toeach of the two cylinders at the ends of the slidable member to move thepistons therein and the two electromagnets in unison in a verticaldirection when the slide is at each end'of its path of travel tosequentially raise and lower the two electromagnets, electrical circuitsto energize the two electromagnets when they are lowered onto the twocore box tops, to maintain the energization of said two electromagnetswhile the two vertically moving pistons are moving upwardly, while theslide is moving to the other end of its path of travel and while thevertically moving pistons are lowered and then to deenergize the twoelectromagnets, and means controlled by said continuously rotatingmember for sequentially operating said slide and parts carried thereby.

7. In an automatic core making machine having a core blowing station,'acore drawing station, a core box top removing station and a core box topreplacing station; a turntable; a plurality of core boxes carried by theturntable; a continuously operating member; means actuated by thecontinuously operating member for intermittently rotating the turntableto said plurality of stations; means at one of said stations forremoving a core box top from a filled core box,

- moving it radially inward and placing it on the turntable; means atanother station for picking up from the turntable a previously removedcore box top, moving it radially outward of the turntable and placing iton the bottom of a core box bottom during the same time interval that acore box top is being removed, moved radially inward and placed on theturntable; means for inverting the bottom of the core box while theturntable is moving from the station at which the top is removed to thecore drawing station and for reinverting the same while the turntable ismoving from the core drawing station to the station at which the corebox top is placed on the bottom part; means controlled by saidcontinuously operating member for automatically operating said means forpicking up a core box top, moving it radially outward and placing it ona core box bottom and for simultaneously therewith actuating the meansfor removing a core box top from a filled core box, moving it radiallyinward and placing it on the turntable; and means controlled by movementof the turntable for actuating said means for inverting and reinvertingthe bottom of a core box.

ROBERT R. SNOW.

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